Method of forming fin vibration damper



Jan. 8, 1952 P, N E| |OTT 2,581,845

METHOD OF FORMING FIN VIBRATION DAMPER Filed Oct. 2, 1948 Patented Jan. '8, 1952 Phillip Elliott; Manchester, onen., assignor to. United Aircraft. (:lorporat'ion-l East' HartfordL Conn., a corporation of Delawaref- Application October 2, 1948, Sjeri'al No. 52,5'81;

This invention relates to a vmetlmxl oity forming a vibration, dam-per on a, :tir-ined, structure, particularly for the cooling fin structure of a cylinderfier an air-cooled internal combustion engine. -However, the method1 herein described is notlimitedf-to acool-ingn-structure, but is applicable to-any finned structure in whichthere isa problenrof nndampening;

rIlheprimaryobject of thi'sinverition is to provide a damperwhichfcairbe-applied tothe ns in the for-m of apaste orplastic,l such asy asilicone rubber compound, and then cured' toy adhere to the Slalliadeofj the AThis has the advantage that it carr be used on iins having complex shapes and contoilrswhere it-.WQudl be extremely diiil'cult or impossible to apply preformed braces or damper pads of the type known in the prior art.

A further object is to provide a n damper which is light in weight and which will not damage the ns as sometimes occurs where metal dampers are used.

Still another object is to provide a damper which can easily be repaired, as by patching, and which does not require careful or special machining of the nhs.

Other objects of this invention will become apparent and the invention will be better understood from the following description in connection with the drawings in which:

Fig. 1 is a perspective view of a nned body with the invention applied thereto, and

Fig. 2 is a section taken on the line 2-2 showing the nned body and the nal form of the lin damper.

The preferred embodiment of the invention is disclosed in the drawings in which the reference numeral 2 indicates a body, such, for example, as the wall of a cylinder of an air-cooled internal combustion engine, having a series of spaced cooling iins, extending outwardly therefrom. It has been found in practice that a certain engine speeds sympathetic vibrations are set up in the cooling ns which may at times cause them to crack and fail. It is therefore desirable to provide some means to dampen such vibrations and hence increase the life of the engine and the safety of its operation. To this end the damper 3 is applied to the fins as shown in Figs. l and 2.

The drawings show the lfin damper 3 in position in its inal form on the lins I of engine cylinder 2. These iin dampers are formed of a proper curable compound, such as a silicone rubber compound, Vthis same compound with asbes- 3 Claims. (Cl. 18-59) 2 tos fibra added to increase its resistance to heat, orV a phenoIic 'resin-thiokol rubber dispersion compound. TheV selection of a compoundfor use asr a 1iny damper may be determined by the tempera-tures to:- which it isr to be subjected. For example, for the fins of a cylinder of an internal combustionengine, a silicone rubber compound is` used, as4 it canwithstandthe high temperatures reached b-y the ns. For` a finned body not subjected to such high'` temperatures the phenolic resin-thiokol 1 rubber dispersion compound can be used?. In cases where extremelfy high temperatures are reached; asbestosniibresr may be added: tothe' compound tol increaseitsf. resistance to. heat, as* mentionedf before.` The compound tobe used can loe-applied in several dierent ways, all coming within the scope of this. invention.

First, this compound can be spread down a line in the form of a paste, using a blade or trowel, connecting the ns (as shown in the figures) upon which a damper pad is desired. To obtain an even sided iinished damper pad using this paste, two strips of masking tape are laid down on the outer surfaces of the ns allowing for the width of damper pad desired, and then the paste is spread down between the strips of tape. When the tape is lifted it leaves the damper pad with straight, even sides. However, this is merely to improve the appearance of the damper pad and the pad may be formed with uneven sides, if desired, without affecting its performance.

Second, a pre-formed strip of such a material can be prepared, either uncured or partially cured, and then pressed into place as shown in Figs. 1 and 2. When this strip of prepared material is used, it can be reinforced with a tape applied either to the back side of the strip or sandwiched between two layers of the material. Instead of being pressed into the rlns, the strip form can be rolled on with a roller. This leaves a cross-section similar to the one as shown in Fig. 2, noting inwardly bulging portions 4. This strip can be pressed or rolled to any desired thickness; If a large bonding area between the material and iins is desired the pad can be applied so as to increase the depth to which it extends between the fins.

Next the damper must be properly cured. This is accomplished by heating the fins and the damper strip to the proper temperatureand for a time necessary to cause the damper strip to adhere or become bonded to the metal ns. It has been found that the curing time or cycle bonded or adhered to the fins. The nal curing'V step may be accomplished by the heat developed in the finned body itself. For an example, `a damper pad can be applied to the ns of a cylinder of an internal combustion engine by one Vof the methods described above, and cured by the heat developed during the operation of the engine. f

I claim:

, 1. The method of forming a iin damper on a series of ns on a nned body to dampen vibrations thereof which comprises placing a strip of a curable rubber compound in a plastic state onto said fins, regulating the distance the portion of the strip between the fins extends from the edges of said fins towards the body to prevent complete lling of the spaces between the ns, and curing said strip until it becomes resilient and adhered to said ns.

l 2. The method of forming a n damper on a series of fins on a iinned body to dampen vibrations thereof which comprises placing a strip of a curable rubber compound in a plastic state against the edge of a series of fins, working Vsaid 3 portion of the strip between the ns extends from the edges of said ns towards the body to prevent complete lling of the spaces between the ns. and curing said strip until it becomes resilient and adhered to said fins.

3. 'I'he method of forming a iin damper on a nned body to dampen vibrations thereof which comprises placing a rubber compound in a plastic state against the edge of a series of ns, working said compound onto said fins, regulating the distance the portion of the compound between the fins extends from the edges of said iins towards the body to prevent complete lling of the spaces between the ns and curing said compound until it becomes resilient and adhered to said ns.

PI-IILLIP N. ELLIOTT.

REFERENCES CITED The Vfollowing references are of record in the le of this patent:

v UNITED STATES PATENTS Number Name Date 817,993 Rueter Apr. 17, 1906 1,578,793` Apple Mar. 30, 1926 1,739,246 Majce Dec. 10, 1929 1,913,328 Bollman June-6, 1933 2,218,351 Crowell Oct. 15, 1940 2,253,025 Fedden et al. Aug. 19, 1941 2,351,329 Gerstenmaier June 13, 1944 2,455,708 Sherwin Dec. 7, 1948 FOREIGN PATENTS Number Country A Date Y Great Britain Mar. 12, 1937 

